Generally, the roof structure of an automotive vehicle includes a roof panel supported by at least one structural member such as a roof rail. At its edges, the roof panel abuts and is joined to body side panels. The body side panels extend along the sides of the vehicle. Conventionally, the roof panel is joined to the body side panel by overlapping edges of the respective panels and using fasteners, such as rivets, to join the panels. Welding may also be used to join adjacent panels.